The Babel seqno request code keeps track of which seqno requests are
outstanding for a neighbour by putting them onto a per-neighbour list. When
reusing a seqno request, it will try to remove this node, but if the seqno
request in question was a multicast request with no neighbour attached this
will result in a crash because it tries to remove a list node that wasn't
added to any list.

Fix this by making the list remove conditional. Also fix neighbor removal
which were changing seqno requests to multicast ones instead of removing
them.

Fixes: ebd5751c ("Babel: Seqno requests are properly decoupled from
neighbors when the underlying interface disappears").

Based on the patch from Toke Høiland-Jørgensen <toke@toke.dk>,
bug reported by Stefan Haller <stefan.haller@stha.de>, thanks.

Use timer (configurable as 'gc period') to schedule routing table
GC/pruning to ensure that prune is done on time but not too often.

Randomize GC timers to avoid concentration of GC events from different
tables in one loop cycle.

Fix a bug that caused minimum inter-GC interval be 5 us instead of 5 s.

Make default 'gc period' adaptive based on number of routing tables,
from 10 s for small setups to 600 s for large ones.

In marge multi-table RS setup, the patch improved time of flushing
a downed peer from 20-30 min to <2 min and removed 40s latencies.

We currently do not have FreeBSD CI workers.

Thanks to Luiz Amaral for the idea.

The prefix hash table in BGP used the same hash function as the rtable.
When a batch of routes are exported during feed/flush to the BGP, they
all have similar hash values, so they are all crowded in a few slots in
the BGP prefix table (which is much smaller - around the size of the
batch - and uses higher bits from hash values), making it much slower due
to excessive collisions. Use a different hash function to avoid this.

Also, increase the batch size to fill 4k BGP packets and increase minimum
BGP bucket and prefix hash sizes to avoid back and forth resizing during
flushes.

This leads to order of magnitude faster flushes (on my test data).

Toke Høiland-Jørgensen authored 2 years ago and Ondřej Zajíček committed 2 years ago

The debug output was not updated with the rest of the code, so packets.c
fails to compile if LOCAL_DEBUG is set.

Toke Høiland-Jørgensen authored 2 years ago and Ondřej Zajíček committed 2 years ago

When shutting down a Babel instance we send a wildcard retraction to make
sure all peers can quickly switch to other route origins. Add another small
optimisation borrowed from babeld: sending a Hello message (along with the
retraction) with a very low interval.

This will cause neighbours to modify their expiry timers for the node's
state to quickly time it out, thus conserving resources in the network.

When BIRD was munmapping too many pages, it sometimes aborted, saying
that munmap failed with "Not enough memory" as the address space was
getting more and more fragmented.

There is a workaround in place, simply keeping that page for future use,
yet it has never been compiled in because I somehow forgot to include
errno.h. And because I also thought that somebody may have ENOMEM not
defined (why?!), there was a check which quietly omitted that
workaround.

Anyway, ENOMEM is POSIX. It's an utter nonsense to check for its
existence. If it doesn't exist, something is broken.

Add BFD protocol option 'strict bind' to use separate listening socket
for each BFD interface bound to its address instead of using shared
listening sockets.

Thanks to Vincent Bernat for notice.

There were several requests to allow use of 240.0.0.0/4 as a private
range, and Linux kernel already allows such routes, so perhaps we can
allow that too.

Thanks to Vincent Bernat and others for suggestion and patches.

Vincent Bernat authored 3 years ago and Ondřej Zajíček committed 3 years ago

Update the RPM package unit file to check configuration before start and
to use "birdc configure" instead of "kill -HUP".

When birdc is called with a command as an argument, it should set exit
status to non-zero when BIRD replied with an error reply code.

Thanks to Vincent Bernat and others for suggestion.

A recent change in Babel causes ifaces to disappear after
reconfiguration. The patch fixes that.

Thanks to Johannes Kimmel for an insightful bugreport.

For compatibility with older systems use posix_memalign(). We can
switch to aligned_alloc() when we commit to C11 for multithreading.

Alignment of slabs should be at least sizeof(ptr) to avoid unaligned
pointers in slab structures. Fixme: Use proper way to choose alignment
for internal allocators.

After switching to 16-way tries, trie format ignored unaligned / internal
prefixes and only reported the primary prefix of a trie node.

Fix trie format by showing internal prefixes based on the 'local' bitmask
of a node. Also do basic (intra-node) reconstruction of prefix patterns
by finding common subtrees in 'local' bitmask.

In future, we could improve that by doing inter-node reconstruction, so
prefixes entered as one pattern for a subtree (e.g. 192.168.0.0/18+)
would be reported as such, like with aligned prefixes.

The prune loop may may rebuild the prefix trie and therefore invalidate
walk state for asynchronous walks (used in 'show route in' cmd). Fix it
by adding locking that keeps the old trie in memory until current walks
are done.

In future this could be improved by rebuilding trie walk states (by
lookup for last found prefix) after the prefix trie rebuild.

When rtable is pruned and network fib nodes are removed, we also need to
prune prefix trie. Unfortunately, rebuilding prefix trie takes long time
(got about 400 ms for 1M networks), so must not be atomic, we have to
rebuild a new trie while current one is still active. That may require
some considerable amount of temporary memory, so we do that only if
we expect significant trie size reduction.

Add counter of prefixes stored in trie. Works only for 'restricted' tries
composed of explicit prefixes (pxlen == l == h), like ones used in rtables.

Implement flowspec validation procedure as described in RFC 8955 sec. 6
and RFC 9117. The Validation procedure enforces that only routers in the
forwarding path for a network can originate flowspec rules for that
network.

The patch adds new mechanism for tracking inter-table dependencies, which
is necessary as the flowspec validation depends on IP routes, and flowspec
rules must be revalidated when best IP routes change.

The validation procedure is disabled by default and requires that
relevant IP table uses trie, as it uses interval queries for subnets.

Allow to specify sorted flag, trie fla, and min/max settle time.

Also do not enable trie by default, it must be explicitly enabled.

When output of 'show route' command was generated, the net_format() was
called for each network prematurely, even if the result was not needed.

Fix the code to call net_format() only when needed. This makes queries
that process many networks but show only few (e.g. 'show route where ..',
or 'show route count') much faster (like 5x - 10x faster).

Add trie iteration code to rt_show_cont() CLI hook and use it to
accelerate 'show route in <addr>' commands using interval queries.

Implement 'show route in <addr>' command, which shows all routes in
networks that are subnets of given network. Currently limited to IP
network types.

Attach a prefix trie to IP/VPN/ROA tables. Use it for net_route() and
net_roa_check(). This leads to 3-5x speedups for IPv4 and 5-10x
speedup for IPv6 of these calls.

TODO:
 - Rebuild the trie during rt_prune_table()
 - Better way to avoid trie_add_prefix() in net_get() for existing tables
 - Make it configurable (?)

One of previous commits added error logging of invalid routes. This
also inadvertently caused error logging of route loops, which should
be ignored silently. Fix that.